A5029655514- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Adaptive optics and wavefront sensing
- Cosmology and Gravitation Theories
- Solar and Space Plasma Dynamics
- High-pressure geophysics and materials
- Superconducting Materials and Applications
- Relativity and Gravitational Theory
- History and Developments in Astronomy
- Astrophysics and Cosmic Phenomena
- Geophysics and Gravity Measurements
- SAS software applications and methods
- Ionosphere and magnetosphere dynamics
- Magnetic confinement fusion research
- Experimental and Theoretical Physics Studies
- Geophysics and Sensor Technology
- Mechanics and Biomechanics Studies
- Spectroscopy and Laser Applications
- Quantum, superfluid, helium dynamics
Ege University
2014-2023
Netherlands Institute for Radio Astronomy
2022-2023
University of Cambridge
2008-2021
KU Leuven
2005-2014
Izmir Institute of Technology
2009
We collect data on the masses, radii, etc., of three classes close binary stars: low-temperature contact binaries (LTCBs), near-contact (NCBs), and detached (DCBs). restrict ourselves to systems in which (1) both components are, at least arguably, near main sequence, (2) periods are less than a day, (3) there is spectroscopic photometric analysis leading reasonably reliable data. discuss possible evolutionary connections between these classes, emphasizing roles played by mass loss angular...
ABSTRACT We present a binary evolution study of cataclysmic variables (CVs) and related systems with white dwarf (WD) accretors, including for example, AM CVn systems, classical novae, supersoft X-ray sources (SXSs), giant donor stars. Our approach intentionally avoids the complications associated population synthesis algorithms, thereby allowing us to first truly comprehensive exploration all subsequent pathways that zero-age CVs might follow (assuming fully non-conservative, Roche-lobe...
The analysis of eclipsing binaries containing non-radial pulsators allows: i) to combine two different and independent sources information on the internal structure evolutionary status components, ii) study effects tidal forces pulsations. KIC 3858884 is a bright Kepler target whose light curve shows deep eclipses, complex pulsation patterns with frequencies typical {\delta} Sct, highly eccentric orbit. We present result photometry high resolution phaseresolved spectroscopy. Spectroscopy...
The Event Horizon Telescope (EHT) Collaboration recently published the first images of supermassive black holes in cores Messier 87 and Milky Way galaxies. These observations have provided a new means to study probe physical processes occurring strong-field regime. We review prospects future theoretical studies hole systems with next-generation (ngEHT), which will greatly enhance capabilities existing EHT array. enhancements open up several previously inaccessible avenues investigation,...
Aims. We selected a large sample of O-B stars that were considered as (candidate) slowly pulsating B, β Cep, and Maia after the analysis their hipparcos data. analysed our new seven passband geneva data collected for these during first three years scientific operations mercator telescope. performed frequency 28 targets with more than 50 high-quality measurements to improve variability classification. For stars, we tried both identify modes search rotationally split modes.
We present our findings based on a detailed analysis for the binaries of Hyades, in which masses components are well known. fit models binary system to observations so as give observed total V and B-V that slope main-sequence corresponding parts. According findings, there is very definite relationship between mixing-length parameter stellar mass. The fitting formula this can be given $alpha = 9.19 (M/M_sun-0.74)^{0.053}-6.65$, valid greater than 0.77 M_sun. While no strict information...
We present multi-colour time-series CCD photometry of the solar-age galactic open cluster M67 (NGC 2682). About 3600 frames spread over 28 nights were obtained with 1.5 m Russian-Turkish and 1.2 Mercator telescopes. High-precision observations close binary stars AH Cnc, EV ES $\delta$ Scuti type systems EX Cnc EW some long-period variables belonging to are presented. Three full light curves overcontact during three observing seasons. Likewise we gathered an EB-type binary, two a blue...
CONTEXT: Recent progress in the seismic interpretation of field beta Cep stars has resulted improvements physics stellar structure and evolution models massive stars. Further asteroseismic constraints can be obtained from studying ensembles a young open cluster, which all have similar age, distance chemical composition. AIMS: To improve our comprehension stars, we studied cluster NGC 884 to discover new B-type pulsators, besides two known other variable METHODS: An extensive multi-site...
Light curves and photometric solutions of the contact binary XY Leo are presented. The UBVR light appear to be almost symmetric. B V were analysed with Wilson-Devinney code orbital parameters system obtained compared those in previous studies. All times minimum collected combined new ones this study. period oscillates a 19.6 years semi-amplitude 0.023 day. This regular change was under assumption third body hypothesis. time delay advance due orbit eclipsing pair around component computed...
We present ground-based photometry of the low-temperature contact binary BB Peg. collected all times mid-eclipse available in literature and combined them with those obtained this study. Analyses data indicate a period increase × 10-8 days yr-1. This Peg can be interpreted terms mass transfer 2.4 M⊙ yr-1 from less massive to more component. The physical parameters have been determined as Mc = 1.42 M⊙, Mh 0.53 Rc 1.29 R⊙, Rh 0.83 Lc 1.86 L⊙, Lh 0.94 L⊙ through simultaneous solutions light...
Abstract In this study we determined precise orbital and physical parameters of the very short‐period low‐mass contact binary system CC Com. The are obtained by analysis new CCD data combined with archival spectroscopic data. cool hot components derived as M c = 0.717(14) ⊙ , h 0.378(8) R 0.708(12) 0.530(10) L 0.138(12) 0.085(7) respectively, distance is estimated 64(4) pc. times minima in those published before enable us to calculate mass transfer rate between which 1.6 × 10 –8 yr –1 ....
The observed masses, radii and temperatures of 60 medium- to long-period binaries, most which contain a cool, evolved star hotter less-evolved one, are compared with theoretical models include (a) core convective overshooting, (b)mass loss, possibly driven by dynamo action as in RS CVn (c) tidal friction, including its effect on orbital period through magnetic braking. A reasonable fit is found about 42 cases, but 11 other cases the primaries appear have lost either more mass or less than...
We present a detailed photometric study of the low-temperature contact binary V781 Tau, and near-contact V836 Cyg. have combined parameters obtained from light-curve analysis with those found by spectral studies we determined orbital physical stars. collected times mid-eclipses so far in this study. By analysing all these data mass transfer rate massive star to less one for component case Finally, compared results Tau Cyg similar systems.
We present four seasons' (2000–2003) ground-based photometry of the short-period contact binary V2388 Oph. The system is brighter component visual HIP 87655. magnitude difference between companion and eclipsing pair was estimated to be , in B, V R bandpasses, respectively. light curves BVR are solved by WD code. Combining parameters found curve analysis with those radial velocity solution we derived masses radii star components as: . primary appears more evolved mass-radius, mass-luminosity...
Aims.Our goal was to improve the fundamental parameters of massive close double-lined eclipsing B2.5V+B2.5V binary CV Velorum.
We present photometric and spectroscopic data analysis orbital period study of an early-type interacting binary system V382 Cyg by using all the available data. made a simultaneous light radial velocity curve solution. The derived physical parameters primary secondary stellar components are $M_{1}$ = 27.9(5) $M_{\odot}$, $M_{2}$ 20.8(4) $R_{1}$ 9.7(2) $R_{\odot}$, $R_{2}$ 8.5(2) $\log{(L_1/L_{\odot})} 5.152(20)$ $\log{(L_2/L_{\odot})} 4.954(19)$ while separation is {\it a} 23.4 $R_{\odot}$....
We present the Kepler photometric light-variation analysis of late-type double-lined binary system V568 Lyr that is in field high metallicity old open cluster NGC 6791. The radial velocity and high-quality short-cadence light curve are analysed simultaneously. masses, radii luminosities component stars M1 = 1.0886 ± 0.0031 M⊙, M2 0.8292 0.0026 R1 1.4203 0.0058 R⊙, R2 0.7997 0.0015 L1 1.85 0.15 L⊙, L2 0.292 0.018 L⊙ their separation a 31.060 0.025 R⊙. distance to 6791 determined be 4.260...
Almost a hundred compact binary mergers have been detected via gravitational waves by the LIGO-Virgo-KAGRA collaboration in past few years providing us with significant amount of new information on black holes and neutron stars. In addition to observations, numerical simulations using newly developed modern codes field wave physics will guide understand nature single degenerate systems highly energetic astrophysical processes. We here presented set fully general relativistic hydrodynamic...
We present observations and analysis of an RS CVn-type double-lined eclipsing binary system, RU Cnc. The system has been observed for over a century. high-quality long-cadence \emph{Kepler} K2 C5 C18, newly obtained observations, two radial velocity curves were combined analyzed simultaneously assuming multi-spot model. masses, radii luminosities the component stars are precisely as $M_\textrm{c} = 1.386\pm0.044\, M_{_\odot}$, $M_\textrm{h} 1.437 \pm 0.046\, M{_\odot}$, $R_\textrm{h} 2.39\pm...
In this study we present photometric and spectroscopic variation analysis orbital period of a low-mass interacting system OO Aql. Simultaneous solution the light radial velocity curves provide us determination new set stellar physical parameters for primary secondary companion as M$_{1}$ = 1.05(2) M$_{\odot}$, M$_{2}$ 0.89(2) R$_{1}$ 1.38(2) R$_{\odot}$, R$_{2}$ 1.28(2) $\log{(L_1/L_{\odot})} 0.258$ $\log{(L_2/L_{\odot})} 0.117$ separation components were determined 3.333(16) R$_{\odot}$....